2pdr QF Mk.IIc (40 mm)

The 2pdr QF Mk.IIc (40 mm) on the HMS Jervis.

Description

The 40 mm 2pdr QF Mk.IIc, nicknamed the "pom-pom", is a British naval autocannon, used as a primary armament for coastal ships and an anti-aircraft weapon on bluewater ships.

Despite the similar name, this weapon has no relation to the 40 mm QF 2-pounder used on British tanks.

General info

The 2pdr "pom-pom" autocannon is a 40 mm anti-air autocannon that entered service with the Royal Navy in 1917. The gun is belt-fed with 56 rounds capacity per belt and a rate of fire of 200 rounds per minute. The gun was usually found in either a single-mounted version on coastal boats and early destroyers, as well as a quad-mount version found on a British wartime destroyers.

Available ammunition

The 40 mm 2pdr QF Mk.IIc has 3 belt choices, Universal, 40 mm HE, and 40 mm AP.

• Universal: HEF · AP-T · HEF · AP-T
• 40 mm HE: HEF · HEF · HEF · AP-T
• 40 mm AP: AP-T · AP-T · AP-T · HEF

Penetration statistics
Ammunition	Penetration @ 0° Angle of Attack (mm)
	10 m	100 m	500 m	1,000 m	1,500 m	2,000 m
HEF	3	3	3	3	3	3
AP-T	60	57	48	39	32	26

Shell details
Ammunition	Velocity (m/s)	Projectile mass (kg)	Fuse delay (m)	Fuse sensitivity (mm)	Explosive mass (TNT equivalent) (g)	Ricochet
						0%	50%	100%
HEF	701	0.82	0	0.1	71	79°	80°	81°
AP-T	701	0.91	-	-	-	47°	60°	65°

Comparison with analogues

• QF Mark V (40 mm): The Bofors autocannons is mostly superior than the pom-pom in almost every way. The Bofors have a more powerful rounds, higher shell velocity, and features an auto-feeding mechanism that enable it to fire continuously. While the pom-pom technically has higher rate of fire than the Bofors (200 vs. 156 rpm), the lack of auto-feed mechanism reduces the actual rate of fire of the pom-pom to 115 rpm.

Usage in battles

The 2pdr pom-pom performs remarkably well for a gun originated from the Great War era. The gun has superior rate of fire than that of the famous Bofors autocannons, though it is handicapped by the lack of auto-feeding mechanism and low shell velocity which reduced the range of the guns to 3 km at best.

For the most part, the pom-pom's usage is similar to that of the Bofors, with a few distinctive differences. As the gun will never jam due to the belt-fed mechanism, the pom-pom performs better with a short but rapid burst to quickly dispatch the opponents, but the frequent reload will reduce the gun's effectiveness, especially when the enemy is getting too close. Thus, the pom-pom often requires trigger discipline at closer range to accurately hit and destroy the targets before they can attack with bombs or torpedoes.

Pros and cons

Pros:

• Powerful HE rounds
• High rate of fire
• Belt-fed mechanism ensure that the gun will never jam

Cons:

• Low muzzle velocity limits its effective range
• Lacks autoloading mechanism, have to reload semi-frequently

History

Examine the history of the creation and combat usage of the weapon in more detail than in the introduction. If the historical reference turns out to be too long, take it to a separate article, taking a link to the article about the weapon and adding a block "/History" (example: https://wiki.warthunder.com/(Weapon-name)/History) and add a link to it here using the main template. Be sure to reference text and sources by using <ref></ref>, as well as adding them at the end of the article with <references />.

Media

Excellent additions to the article would be video guides, screenshots from the game, and photos.

See also

• 2pdr QF Mk.VIII (40 mm) - Later variant of the weapon
• 40 mm/62 Vickers (40 mm) - Japanese version
• 40 mm/39 Vickers-Terni mod.1915/1917 (40 mm) · 40 mm/39 Vickers-Terni mod.1915/1917, Modif.1930 (40 mm) - Italian licensed versions

External links

• [NavWeaps] 2-pdr [4 cm/39 (1.575")] QF Mark II, Mark II* and Mark II*C (Web Archive)

USSR naval cannons
20 mm	ShVAK
25 mm	2M-3
30 mm	AK-230 · 30 mm/54 AK-630 · 30 mm/54 AK-630M · BP "Plamya"
37 mm	37 mm/67 70-K · V-11
45 mm	45 mm/46 21-K · 45 mm/68 21-KM · 45 mm/89 SM-20-ZIF · 45 mm/89 SM-21-ZIF
57 mm	AK-725
75 mm	75 mm/50 Canet patt.1892
76 mm	34-K · 39-K · 76 mm/60 AK-176M · AK-726 · D-56TS · F-34 · Lender AA gun, pattern 1914/15
85 mm	85 mm/52 92-K · 85 mm/54.6 ZIS-C-53 · 90-K
100 mm	100 mm/56 B-34 · 100 mm/70 SM-5-1 · Minizini
102 mm	Pattern 1911
120 mm	120 mm/50 pattern 1905
130 mm	130 mm/55 pattern 1913 · 130 mm/58 SM-2-1 · B-13
152 mm	152 mm/57 B-38
180 mm	180 mm/57 B-1-P · 180 mm/60 B-1-K
305 mm	12-inch/52 pattern 1907 · 305 mm/54 B-50
356 mm	14-inch/52 pattern 1913 (356 mm)
	Foreign:
40 mm	2pdr QF Mk.IIc (Britain) · Skoda (Czechoslovakia)
47 mm	3 pdr QF Hotchkiss (Britain)
76 mm	76 mm/40 Ansaldo mod.1917 (Italy)
88 mm	SK C/30 (Germany)
120 mm	120 mm/50 Mk.4 Bofors M1924 (Sweden) · 120 mm/50 O.T.O. Mod.1933 (Italy)
152 mm	152/53 mm O.T.O. Mod.1929 (Italy)
320 mm	320 mm/44 Ansaldo model 1934 (Italy)

France naval cannons
37 mm	37 mm/50 model 1925 · 37 mm/50 model 1933
47 mm	3 pdr QF Hotchkiss
57 mm	57 mm/60 ACAD Mle 1951
75 mm	75 mm/50 Canet model 1891 · 75 mm/50 model 1922
90 mm	90 mm/50 model 1926
130 mm	130 mm/40 model 1919
138.6 mm	138.6 mm/55 model 1910 · 138.6 mm/40 model 1927 · 138.6 mm/50 model 1929 · 138.6 mm/50 model 1934 R1938
152 mm	152 mm/55 model 1930
155 mm	155 mm/50 model 1920
203 mm	203 mm/50 model 1924
305 mm	305 mm/45 model 1906-10
340 mm	340 mm/45 model 1912
	Foreign:
20 mm	2 cm/65 C/38 (Germany) · 2 cm/65 Flakvierling 38 (Germany) · 20 mm/70 Oerlikon Mk.II (USA/Britain)
40 mm	2pdr QF Mk.IIc (Britain) · 2pdr QF Mk.VIII (Britain) · Bofors L/60 Mark 2 (USA) · Bofors L/60 Mark 3 (USA)
87.6 mm	Ordnance QF 25pdr (87.6 mm) (Britain)
102 mm	4 in QF Mark V (Britain) · 4 inch/45 Mark XVI (Britain)
105 mm	SK C/33 AA (Germany)
128 mm	12.8 cm/45 SK C/34 (Germany)
150 mm	15 cm/48 KC/36 (Germany)